kohler 231s
Kohler (and all other engine manufacturers) [obviously] balance their engines at the factory. The crankshafts' counterweights are equally balanced to the weight of the piston assembly to reduce engine vibration. The crankshafts that's are used in the12hp, 14hp, 16hp [valves in block] and 18hp OHV (Over Head Valve) engines have the same stroke. The crankshaft in the 14hp and 16hp flathead cast iron block Kohler engine, and the 18hp OHV cast iron block Kohler engine are identical (except perhaps for the PTO end). Therefore, they're balanced the same and can be used in either engine. All these engines have the same stroke, too. Only the counterweights are different. More metal is removed (drilled and machined off) from the counterweights for the 12hp engines, which use a lighter weight piston. The 12hp crank and piston assembly are a balanced set. Kohler uses the same identical piston in their 16hp [valves in block] and 18hp OHV engines. Although their connecting rods are made of different material, they weigh the same. Therefore, the cranks are balanced the same. The wrist pin is narrower in the 16hp and 18hp piston, making them the same weight as the 14hp piston and pin. Therefore, the same crankshaft can be used with the 14hp, 16hp and 18hp OHV piston assembly. If both counterweights on your crankshaft aren't machined off flat, then it's a 14 or 16hp crank. If they are machined off, then it's a 12hp crankshaft. And a 12hp crank shouldn't be used with a 14 or 16hp piston assembly. The engine will vibrate more than usual and because of the heaver piston assembly, the connecting rod could stretch and eventually break. If a 14 or 16hp crank is used with a 12hp piston, because of the heavier counterweights, the crankshaft could eventually break. Because there's one opposing force working against the other.In other words, the 12hp crankshaft is balanced differently from the 14, 16hp flatheads and the 18hp OHV engine crankshafts. Although the stroke and rod journal are the same, the counterweights on the 12hp crank are different. The 12hp piston assembly weighs less than the 14, 16 and 18hp piston assemblies. Therefore, the 14, 16 and 18hp crankshafts need more metal on the counterweights to balance out equally. And 14, 16 and 18hp crankshafts are all balanced the same, which means that they're interchangeable between the 14, 16 and 18hp engines:thinking:Mac.
